(1) Industrial Field of the Invention
The present invention relates novel liquid-crystalline polymers. Particularly, the present invention relates to liquid-crystalline polymers which not only exhibit a ferroelectricity even at temperatures in the vicinity of room temperature but also have a high speed in responding to external factors enabling to display motion pictures and can be advantageously used as display elements of large size screens and curved screens. Such liquid-crystalline polymers are useful in optoelectronics fields, especially as electronic optical devices such as display elements for electronic desk calculators, clocks and watches, etc., electronic optical shutters, electronic optical diaphragms, optical modulators, optical-path transfer switches in optical communication systems, memories, liquid crystal printer heads, varifocal lenses, etc.
(2) Description of the Prior Art
Display elements in which low molecular weight liquid crystals are employed have been widely used for digital display of electronic desk calculators, clocks and watches, etc. In these fields of application, such conventional low molecular weight liquid crystals are generally sandwiched between two glass substrates spaced in microns. Such an adjustment of the space however is impossible to applying to large size screens and curved screens. In order to solve the problem, it has been attempted as one way to develop polymeric liquid crystals which per se are moldable (J. Polym. Sci., Polym. Lett., Ed. 13, 243(1975), Polym. Bull., 6, 309 (1982), Japanese Patent Application Laid-open No. 21479/80, etc.).
However, these liquid crystal polymers generally have a disadvantage in low response speed of the changes of transmission intensity and the like to the changes of external factors such as electric field, and therefore no satisfactory liquid crystal polymer has been obtained.
The liquid crystal polymer disclosed in the above-mentioned Japanese Patent laid-open also have a disadvantage in that the polymer itself cannot exhibit liquid-crystalline properties at room temperature and should be heated at temperatures not lower than glass transition temperature and lower than clearing temperature to make it be liquid crystal state.